Hitachi, Ltd.

Hitachi Car Engineering Co., Ltd.

Hiroshi Odakura

Masami Abe

Satoshi Usui

Hiroyuki Yamada

Atsuji Saito

Toru Onose

Masayoshi Kotaki

Kenichiro Tokuo

Usui Satoshi

Masami Hitachi Car Eng Co Ltd Abe

The objective of the present invention is to dampen operating sounds of an electromagnetic drive mechanism used for a variable displacement to reduce an individual difference depending on apparatus due to the control mechanism in a high-pressure fuel supply pump change over time or installation tolerance. To achieve the above objective, the present invention is configured such that before the electromagnetic drive mechanism supplies a drive force to a plunger which is electromagnetically driven by the electromagnetic drive mechanism, another displacement force situates the plunger in a specific position. When compared to an occasion where the plunger is displaced all strokes by a magnetic biasing force, the above configuration is able to reduce the force of impact on a member (for example, valve body) mounted to the plunger and a restricting member, thereby damping the collision noise. Furthermore, since an extra member, such as a damping member, is not required, individual difference depending on apparatus do not easily occur.

Electromagnetic drive mechanism and a high-pressure fuel supply pump

A fluid pump has a cylinder supporting a plunger and a pump housing formed with dissimilar metals. A pressing mechanism presses the cylinder and the pump housing relative to each other so that a pressurizing chamber is sealed through a pressing surface between the pump housing and the cylinder. The number of seal points can be reduce, and a reduction in reliability can be eliminated while realizing a reduction in weight of the pump housing and a reduction in cost due to increase in cutting capability, by using a soft material such as an aluminum alloy for the pump housing.

Fluid pump and high-pressure fuel feed pump

A high pressure fuel pump for an internal combustion engine having a cylinder, a plunger slidably fitted in the cylinder and a seal mechanism for blocking fuel leakage from an end of a sliding portion between the cylinder and the plunger and also for preventing an lubricant for a driving mechanism of the plunger from entering into the cylinder from the end of the sliding portion of the cylinder and the plunger. A holder surrounding the end of the sliding portion of the cylinder and the plunger is provided. The seal mechanism comprises two mutually independent seal devices mounted with a specific spacing in a longitudinal direction from the end of the sliding portion of the cylinder and the plunger along a circumference of the plunger. The two seal devices are held on the circumference of the plunger by the holder surrounding the end of the sliding portion of the cylinder and the plunger while keeping the specific spacing.

High pressure fuel pump for internal combustion engine

A fuel feed system capable of feeding a fuel to fuel injection valves at a fuel pressure with improved stability is provided. A fuel feed system for an internal combustion engine including a fuel tank and a low-pressure pump for feeding the fuel in the fuel tank to fuel injection valves, is provided with a diaphragm type damper having a wave-shape cross section at a position in contact with the fuel. Also, in a high-pressure fuel feed pump including a pressurizing chamber for pressurizing the fuel, a plunger for pumping the fuel within the pressurizing chamber, an intake valve provided at a fuel inlet of the pressurizing chamber, a discharge valve provided at a fuel outlet of the pressurizing chamber, and a low-pressure chamber provided in an upstream of the intake valve, a mechanism for reducing fuel pressure pulsation is disposed in a space of the low-pressure chamber provided in the upstream of the intake valve, and a fuel pressure sensor for measuring the fuel pressure is mounted near the mechanism for reducing fuel pressure pulsation.

High pressure fuel pump provided with damper

The objective of the present invention is to dampen operating sounds of an electromagnetic drive mechanism used for a variable displacement control mechanism in a high-pressure fuel supply pump to reduce an individual difference depending on apparatus due to the change over time or installation tolerance. To achieve the above objective, the present invention is configured such that before the electromagnetic drive mechanism supplies a drive force to a plunger which is electromagnetically driven by the electromagnetic drive mechanism, another displacement force situates the plunger in a specific position. When compared to an occasion where the plunger is displaced all strokes by a magnetic biasing force, the above configuration is able to reduce the force of impact on a member (for example, valve body) mounted to the plunger and a restricting member, thereby damping the collision noise. Furthermore, since an extra member, such as a damping member, is not required, individual difference depending on apparatus do not easily occur.

Fuel feed system

A simple structured high-pressure fuel pump. A fuel pump comprises a reciprocably-supported cylinder, a pressurizing chamber using part of the outer surface of the cylinder as the wall surface which move to change the internal volume, a fuel intake passage forming a fuel passage which introduces fuel to the pressurizing chamber, a fuel discharge passage for the compressed fuel coming out from the pressurizing chamber. A fuel intake valve is provided in fuel intake passage. A fuel discharge valve is provided in said fuel discharge passage. A connecting passage connects upstream side of the intake valve in the fuel intake passage and the downstream side of it. A check valve which flows fuel from the fuel discharge flow passage to the fuel intake passage is provided in the connecting passage.

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Hitachiota, Japan

Hiroshi Odakura